From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1B44ECDFBB for ; Wed, 18 Jul 2018 21:27:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D7882084E for ; Wed, 18 Jul 2018 21:27:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4D7882084E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730383AbeGRWHb (ORCPT ); Wed, 18 Jul 2018 18:07:31 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:59626 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729209AbeGRWHb (ORCPT ); Wed, 18 Jul 2018 18:07:31 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1DCE681A4EBF; Wed, 18 Jul 2018 21:27:45 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-116.rdu2.redhat.com [10.10.120.116]) by smtp.corp.redhat.com (Postfix) with ESMTP id B9A702156893; Wed, 18 Jul 2018 21:27:43 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <20180718025636.GA26175@ZenIV.linux.org.uk> <20180718132955.2bf185b7@canb.auug.org.au> <20180718124340.GS30522@ZenIV.linux.org.uk> <20180718181252.GU30522@ZenIV.linux.org.uk> <20180718194637.GV30522@ZenIV.linux.org.uk> <20180718200411.GW30522@ZenIV.linux.org.uk> To: Linus Torvalds Cc: dhowells@redhat.com, Al Viro , Miklos Szeredi , Stephen Rothwell , linux-fsdevel , Linux Kernel Mailing List Subject: Re: [RFC] call_with_creds() MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <15537.1531949263.1@warthog.procyon.org.uk> Date: Wed, 18 Jul 2018 22:27:43 +0100 Message-ID: <15538.1531949263@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Wed, 18 Jul 2018 21:27:45 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Wed, 18 Jul 2018 21:27:45 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'dhowells@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds wrote: > and then read/write/open could just inc/dec the cred_poison counter > (when the debug option is set). As I may have said, I have tried modifying the kernel to pass the cred pointer down. The drivers and ioctl() implementations are/were particularly nasty in this respect. So many of them were doing checks against the current thread, not f_cred. I think I need to work out some way to automate the process of adding in the extra parameter as it's not something that I think can be trivially done with coccinelle. David